A portable mixer having an open-top, semicircular mixing trough supported by a base fixedly mounted to the mixing trough. The base is provided with a pair of spaced-apart box channels extending through the base for receiving forklift tines. A paddle is positioned within the mixing tub, and is mounted in cantilever fashion to an axle with the paddle mounted in depending relation to the axle. The axle is carried by a bearing located outside the trough and the axle is aligned with the axial center of the semicircular trough. An actuating system is used to rotate the axle back and forth causing the paddle to sweep back and forth within the trough.